Pressure casting machine



APY 3, 1947 4 B. L LEvlNsoN 2,418,649'v PRESSURE CASTING MACHINE Filed Feb. 21 I 1944 Patented Apr. 8, 1947 raEssUnE cas'rmc MACHINE Benjamin L. Ievinson. Great Neck. N. Y., assignor. by mesne assignments, to Solar Aircraft Company, San Diego, Calif., a corporation of California Application February 21, 1944, Serial No. 523,234

1 Claim. (Cl. 22-57) A further prime object of the invention is the y provision of an improved pressure casting machine which may be operated rapidly and emciently, so that the desired castings may be made on a high productionbasis and with repeated uniformity.

The pressure casting machine of the present invention lends itself elciently to the making'of castings, particularly of moderately large size. having uniform denseness and shape accuracy. The produced castings possess both a highly uni form body denseness or body soundness and an accuracy of form or shape, combining also therewith a nished surface or skin. the combination of which reduces and in fact eliminates the need of any subsequent surface machining. Such castings are also found to possess unusual tensile and compression strengths.

The pressure casting machine oi.' the present invention may be used for any type of mold and is here exemplified for use with a ask mold. The flask mold is removably mountable inthe casting machine for the casting operation. In this type of machine, where the casting is small in size or/and simple in shape, the metal is either melted directly in the flask or poured into the iiask in a molten condition, after which the ask is sealed and-the melt placed under pressure for compression filling of the flask mold cavity. While this type of machine has in prior practice served eectively for small or simple shaped castings, dimculties arise where the casting is 2 casting machine of this type. capable of such operation and use. is the prime desideratum of the present invention.

To the accomplishment of these objects and such other objects as may hereinafter appear. the invention relates more particularly to the pressure casting machine sought to be defined in the appended claim and disclosed in the accompanying specication in connection `with the appended drawings in which:

Fig. 1 is an elevational view of the pressure casting machine of the present invention. with parts shown in section;

Fig. 2 is a side view thereof taken in crosssection in the plane of the line 2--2 of Fig. 1;

Fig. 3 is a view of Fig. 1 taken in cross-section in the plane of the line 3 3; and

Fig. 4` is a sectional fragmentary view of a modication thereof.

'Referring now more in detail to the drawings and having reference rst to Figs. 1 to 31 thereof, the casting machine is intended to be used with molds such as the mold M of the flask type. The mold M is of the investment type consisting of a metal ask I0 containing a refractory investment material i2 which has a mold cavity I4 produced therein by the lost wax method, the said mold cavity having branches i6 and i8 communicating with the sprue opening 20. The sprue opening 20 preferably terminates in a funnel shaped end 22 at the pouring end or face of the ask. The flask I0 preferably comprises a tubular elenent open both at its bottom 24 and at its top 2 The flask mold M is removably receivable by the pressure casting machine for a pouring operation. The pressure casting machine generally designated as C comprises a support for` receiving and sealing the mold flask M, said support comprising a stand 28, a seat 30 for the'ilask bottom 24 vertically movable in the stand .28, and a head 32 for the ask top 26 preferably flxed to the stand 28. By the movement of the seat 30, the mold flask M is received in the casting machine and sealed for a pouring operation and is Withdrawn from the casting machine after the metal poured therein has been pressure iilled and solidiiled.

It isV important, particularly in making a large sized or complex casting having the desired variance'in timing introduced which is depend- .able retort or furnace.

ent upon the nature of the metal being cast. It is. therefore, desirable to coordinate such factors as the preconditioned temperature of the mold flask M, the nature of lth'e `pouring channel' or duct, the pressure employed for compression ll-'l ing of the mold cavity, and the time lapse between the pouring step and the step of application of the pressure. Moreover, the operational steps involved should desirably be of such a simple character and carried out with such simple equipy ment that the operator be afforded a sufiicient margin oi? latitude for timely carrying out the' diierent steps of the technique and for varying the timing dependent upon the nature of the metal being cast. l

In the practice of the method, the mold flask M is placed in a suitable furnaceI and heated to elevated temperatures. The particular tem- -peratures to which the ask islheated depends largely upon the melting point of the metal or alloy to be cast. Taking, for example, a high melting point metal or alloy such as stainless steel nace to a temperature of from 500 to 750 F.

While the mold is being heated, the vmetal to be cast is brought up to its melting point in a suit- The -mold M thus `preconditioned is placed into the casing machine C and sealed in position between an asbestos liner 34 in the seat 30 and the asbestos liner 3.6 in the head 32. In this position as shown in Figs. 1 and 2 of the drawings, the mold is ready for a casting operation.

To carry out the objects of the invention, the melted metal is poured by means of a suitable ladle through the head 32 and into the mold cavity of the flask M. To this end the head 32 is provided witha pouring duct 38 which communicates` directly with the sprue opening-20 of the mold cavity, the diameter of this pouring duct preconditioned temperatures of the mold M. The

described diameters for the pouring duct 38 and the funnel F are such that when the metalV is ladled into the funnel and gravitationally ilows therefrom into the flask, the metal will not contact the walls of the pouring duct 38 thereby avoiding any chilling thereof. By means of this construction, therefore, the metal is poured into the mold by way of the casting machine head 32 and through the pouring duct 38 thereof;

After this pouring operation, pressure is ready to be applied to the metal in the mold for compression lling of the mold cavity. It is important to correctly determine within limits the time lapse between the pouring of the metal and the application of the pressure. is comparatively short in any event but may vary within substantially wide limits. Thus, for ex- This time lapse' steel, this time lapse may be as short as 1/6 of a second, while with a low melting pointv such as l aluminum, this time lapse may be as muchas 5 seconds. Afterthe pouring operation,"the apparatus provided is in a condition to have the pressure applied either immediately, such as within the fraction of a second, or within the period of a few seconds. To accomplish this, the head 32 is'provided with \means preferably in the form of a valve for opening the pouring duct 38 for a metal pouring operation and for closing and sealing said duct after such a pouring operation, land is also provided with means for connecting a gas pressure supply to the charging duct and particularly the mold cavityfor placing the same under the desired pressure when the duct has been closed and sealed. To accomplish these ends,l the head 32 is provided with a valve 44 resiliently seated in a valve seat 46 formed in said head and operable by means of a handle 48 fixed to the valve stem. The valve is resili'ently urged into the head by means of a spring 50 which is anchored against a threaded valve holding nipple 52 adjustably mounted in the head. The valve has a port 54 which registers with the pouring duct 38 for opening the same 'when the valve is moved to the position shown -in Figs. 1 and 2 and for closing the same when the valve is moved to a position therefrom. In the position shown in Figs. 1 and 2, the pouring duct 38 is open for a pouring operation, and

when the valve is moved to-the 90 position, the

duct is closed and the mold cavity is sealed.

For connecting the mold cavity to a gas prespressure from the pipe 60 when the valve 44 is in n, the metal pouring position, and which functions to open the mold cavity to the pressure supply when the valve is moved to the 90 position to close and seal the pouring duct. It will be understood that the operator, after ladling the metal through the pouring head, will wait the selected time (from a fraction of a second to several sec-v onds) before he operates the valve 44, and that upon operation of this valve, sealing of the flask will take place with the concomitant application of the air pressure. The degree of air pressure employed depends upon the type of metal being cast. This will vary from 10 pounds for some metals to A35 to 50 pounds 'per square inch for metals such as steel.

The stand 28 may suitably comprise a base plate 64 to which is anchored the supporting posts 66 and 68. The seat 30 is mounted to move ver-` tically' in said posts and the head 32 is fixed to the top of the posts as shown, also thereby serving in conjunction with the bottom plate 64 to produce a rigid stand frame. For moving the seat 30 (for removably mounting and sealing the flask M) I preferably provide the mechanism best shown in Figs. land 2 of the drawings, which comprises a central post 10 externally threaded as shown for vertical adjustment in the correspondingly threaded base plate 64, the post being held in any adjusted position by means of the lock screw 12,.

The post I seats at its top a cam holder Il which is rotatably adjustable in the post and which may be held in any adjusted position by means of the lock screw 16. In the holder 14 is mounted a cam 18 operated by means of a handle 80. The cam engages a spring member ,82 which is bifurcated at its opposite ends 94 and 86 for reception of the posts 66 and 58 and the body of which resiliently engages the movable seat 30. By means of this construction the seat may be elevated (resiliently) by moving the cam 'I8 to the position shown in Figs. 1 and 2 of the drawings and may be lowered (for permitting reception or removal of the flask) by a 180 movement of the cam. The post 10 is adjustable to. accommodate diierent sizes or heights of asks, and the cam holder 14 is adjustably rotatable in the post so that nomatter to what position the post is rotated, the cam 18 may be moved to its correctly aligned position as shown in Figs. 1 and 2 of the drawings.,

In the modiiication shown in Fig. 4 of the drawings, a different form of valve is used in the head' of the casting machine and this valve is not directly connected with the pressure supply. Otherwise the construction as shown ln Fig. 4 is the same as that shown in Figs. 1 to 3 and the parts thereof are designated by the same but primed -reference characters. In this modification the valve comprises a gate or slide valve 98 movable by means of a handle 90, and the pressure supply source is connected directly from the pipe 60' through a manually operable valve 92 to a port 94 leading into the pouring duct 38' at a point below the seat of the gate valve 88.

rThe construction and operation o! the pressure casting machine of the present invention and the described advantages thereof will in the main be fully apparent from ,the above detailed description thereof. The casting machine presents a very simplied piece, of equipment. A large number of these may be arranged in gang formation to be operated or used sequentially by one operator. `The mold or flask for each machine afterl being preheated is quickly placed and sealed into the casting machine by the operation o! the cam handle 80. The operator then ladies his metal into the mold through the preheated flask F and the head of the casting machine; and the structure and operation of the machine are so simplied that the operator may carry out a series of pouring operations for sequentially positioned casting machines. With the timing selected according to the character of metal being cast. the operator may then close the valve in the casting machinehead vand: open themolsl. manually or While I have shown and described preferred emautomatically, to pressure. When the resulting casting is solidified, the flask is removed and the casting detached therefrom. The castings obtainedpossess the described soundness.strength,

shape accuracyl and surface finish.

While I have 'exemplliied fthe invention by reference to the use of the casting machine with iiask molds, it will be understood that other molds could and are intended to be used therewith, such as sand molds, permanent molds or plastic molds.

' bodiments vof the casting machine of the invention, it will be understoodthat changes may be made therein without departing from the spirit of the invention as deilned in the following claim.

I claim:

A pressure casting machine comprising asupport for receiving and sealing a mold, said] support- Y including a stand, a seat for the mold bottom movable vertically in said stand, and a head for the mold top xed to said stand, means for moving said seat for removably receiving said mold, the

means for moving said seat comprising a threaded post vertically adjustable in said' stand, a cam holder rotatably adjustable in said post, an operating cam in said holder, a spring member between said seat and said cam and means for operating the cam. Y

BENJAMIN L. LE'VINSON.

REFEnENcEs' CITED The following references arerof record'in the Y iile oi.' this patent: v

UNITED STATES PATENTS Number German Jan. i2, 1939 

